Certain Raman systems operate with pump wavelengths in the near-infrared (NIR) range (typically wavelengths of 0.7 to 2.5 microns). Such systems have an advantage in certain application spaces in that they reduce the amount of fluorescence signal contamination. A disadvantage, however, is that this wavelength range contains significant and detectable amounts of blackbody radiation which manifests itself as background noise, which can reduce the sensitivity, specificity and accuracy of the Raman measurement. This background is generated from the “scene,” including the surfaces of the instrumentation facing the detector. Typically such surfaces include the inside walls of the detector housing, the window of the detector housing, and any spectrograph surface and components in line of sight to the detector surface.
In typical Raman spectroscopy applications, such as astronomy, industrial process control, pharmaceutical and or bio-pharma composition, process and quality control and the like, the detector can be cooled to well below ambient temperatures, typically using a thermoelectric (TE) stack. While this minimizes dark noise generated within the detector itself, it does not solve problems associated with the undesirable radiation incident upon the detector. Accordingly, there remains a need for further contributions in this area of technology.